OK Bar. Giving this a try. I understand some people with 3d printers are getting better results with pom nuts. My concern is that the plastic will not hold up to the stresses of router use. I also have concers about anto backlash. But that can be measured with electronic height calibration. Slowly lower bit till it touches metal. Then bacl away slowly until loss of contact. That is the backlash. I agree hopefully those numbers will be not si great to start but over time as parts are used can be expected to increase. Where this is really noticed would be when z axis is reversing direction. The backlash can cause wrecked objects by not raising router high enough and mostly ehen using tabs. Routing something without tabs and going all the wat through can be dangerous. Sunce you stated that you have brass nuts but think the pom ones are better. That you might consider packing both and let the user choose which works for them. If someone is just routing foam the pom may be best. But id using hardwood the brass i believe would last longer. Personally, i would have preferred anti backlash nuts for the screws. That is what even came with $99 cheap china router on all axis. But believe some kind of compensation needs to be devised.
Welcome to the forums!!! 
See I’m here before I go over to the KS comments and I’ll never miss a post this way 
They are pretty heavy duty. I ran the same 5mm POM lead screw nuts for the whole last year with no signs of wear, and the 8mm ones should be even more durable. Keep in mind that none of the forces needed to actually do the cutting are passing through the leadscrews. The belts and arms pull directly on the router itself and the leadscrews only support the weight of the router while it’s cutting.
The backlash I’m seeing is on the order of 0.05mm and my tabs are usually about 3mm thick so the backlash doesn’t come even close to preventing tabs from working.
I don’t want to include them in the box by default because I’m betting that more than 50% of people putting the machine together won’t actually read the instructions and might use them by accident, but we will offer brass nuts for free to anyone who wants them.
To be honest the ONLY place I’ve ever seen anti backlash nuts used is on cheap Chinese routers. They are more of a marketing gimmick than a real tool. The real solution to backlash is to use ball-screws, but those are much more expensive and require maintenance.
Here is a quick video of cutting some tabs if that helps to visualize how it works:
At the end of the day I think it’s important to keep in mind what our goals are (which is affordable wood working). Something like using ball screws to eliminate backlash in the lead screws would make a lot of sense if we were trying to make a machine to CNC mill turbine blades or something super precise like that, but since we’re cutting plywood that 0.05mm or less isn’t really an issue.
To be honest the ONLY place I’ve ever seen anti backlash nuts used is on cheap Chinese routers. They are more of a marketing gimmick than a real tool. The real solution to backlash is to use ball-screws, but those are much more expensive and require maintenance.
I’ve seen backlash nuts on more expensive equipment, it’s a step before ball
screws (and sometimes where there is significant side loading that aren’t as
good for ball screws), but with the price of ball screws plummeting, it’s not as
common as it used to be.
Here is a quick video of cutting some tabs if that helps to visualize how it works:
https://www.youtube.com/shorts/eQoABBhridc
At the end of the day I think it’s important to keep in mind what our goals are (which is affordable wood working). Something like using ball screws to eliminate backlash in the lead screws would make a lot of sense if we were trying to make a machine to CNC mill turbine blades or something super precise like that, but since we’re cutting plywood that 0.05mm or less isn’t really an issue.
it’s important to remember that on the maslow, there is constant loading in one
direction.
on the original, we put a bungee cord over the router to provide the constant
force, with the maslow 4 the belts and/or the weight of the router provide a
constant downforce.
the only time this doesn’t fully apply is when you are plunging into the
material, and in an ideal world, you want to pause for a moment at the end of
the plunge anyway to let the cutter settle (the sled could lift away from the
part, something backlash nuts can’t do anything about anyway 
)
David Lang
Thank you Bar. The cheap China is my only experience and kept trying to make improvements. Finally gave up. Hopeful for something better this time. Which would not take much. But know I need something. Tremors in arms and legs took any wood working a long time ago. But getting slowly better. Need to find something as a hobby to get me more active. Days I can be active has shown at least a 50% reduction in need for insulin. To be honest I would never consider a cnc with just 2 legs. But when I saw the 4 belts of the maslow4 I knew I had to contribute. You have much more experience than me. Just saw last night a you tube video for kiri:moto where you made a toolbox tote. Just received a couple of esp32 s3 dev boards. Any chance of getting a copy of operating code to try out. Knowing it is early beta?
Thank you. I am just airing my concerns. For a little while I was concerned about UV radiation when I read up on POM material. As since I do not have a garage my use will have to be outside. But then realized the pom nut is inside other plastic. So I am guessing they will be OK outside when being used.
You can absolutely get a copy of the code. It is available here:
…but it’s not well documented or easy to set up at the moment so I expect it will be a bit of a struggle to get everything working
If I need to can I bring in my laptop for help?
Martha Montgomery
Unfortunately not, we’ve gone down that road in the past and it ends up consuming WAY too much time. Doing anything one on one just isn’t really in our budget, but especially something like setting up the firmware on a dev board which is something most users will never have to do.
When the Maslow4 kit arrives it will already be programmed and all you will need to do is plug it into the power.
If you want to set up the firmware for doing software development it can take days to get all the right libraries installed and make sure everything is working right.
I’m happy to answer any questions here in the forums though.
I have a project . I want to make 4 torsion boxes but minus bottom sheet 2 4ft x4ft and 2 2ft x 8 ft that interling forming an H pattern. 2x8 each end and 4x4 together mKe 4x8 ft canvas as they call it. I have ordered a t guide mechanism to maybe be able to use my geared circular saw if I am able. Also now have a pair of workpro sawhorses that will be the legs for it.
Also have you heard of software that is free called kiri:moto is is supposed to be able to render in .slv and .dwg. but have not tried it yet. Another program I will be able to use if I want is Basic clc suite but only exports to g code.
Martha Montgomery
kiri:moto also is available as a plugin for onshape and can take a variety of
input formats and create gcode for 3d printing, laser cutting, or CNC work.
This is the CAM (Computer Aided Manufacturing) step in the CAD/CAM/CNC pipeline
kiri:moto produces gcode, that’s what the CAM step does.
If you need to get 2d images out of onshape, create a drawing tab and insert the
parts there, you can then export that to dwg/dxf/pdf
why are you trying to get to those formats?
David Lang
Because the cnc at the makerspace that I joined only accepts dwg and slv formats. It looks to be commercial grade with a size of 60"x60".
that means that the software you are using there is the CAM software, so you
shouildn’t be doing the CAM step at all. you want to just go from your CAD
software to the software at the makerspace.
David Lang
It seems to require configuration before allowing to start. Also have cut2d software and aspire trial. All start out wanting to set up configuration to start
Martha Montgomery
I have cat scan in federal way at 3:30. Might be able to stop by after if you are open. They said it would take maybe half hour.
Ops seems i messed up on whom messages got sent to. Thank you Bar for last video. It helps me a lot in confidence with your project. Also undrrstanding problems you are experiencing with misrepresented past models. Also understanding why areas are not being open projects. Your product seems much better than the $4 Goliath cnc even if a vacuum and motor is included. It does cut through some tabs. I do love the concept of this project. Just wonder if a spindle might have been a better choice for the motor. Curious what the 2500mm per minute limitation is and if that might even proceed higher based on high speed router can turn?
Martha Montgomery
I think that Goliath was a really cool project (although a bit over priced)…but they’re not doing the best job of running it. They are 7 years late on delivering to their Kickstarter backers 
… If you want to see some unhappy customers, check out their kickstarter comments section. I think that if they had shipped on time and could get the price below $1k they could have had an amazing product.
The limiting factor is how powerful the motors are. The motors which move the belts can only move the sled that quickly. That also happens to be about how fast most of the routers in this size class are happy cutting. It would be totally possible to build a bigger more powerful version with a little bit of a higher price tag. To me 2500 mm/min and this size / price is a pretty nice sweet spot, but I could imagine doing a more expensive faster version with a spindle in the future for a more professional market (cabinet makers or something like that).
Thank you so much. Very informative. I live in a older mobile home and the fiberboard used to face my cabinets the edges are getting swells. Think I need to at least resurface and paint. I believe your project will work great for that as well as other things around my home. But that likely first project once I have frame figured out. Might less gears on the drive motors with horizontal routing and a spindle really make for a fast machine
Martha Montgomery
The maslow is not really good for resurfacing. Since the sled rides on the
material that’s being cut, fully removing the surface will have the effect of
lowering the cutter.
David Lang
To some effect you are right. But put rails on the sides if the cabinet so the sled is elevated and sliding on the side supports and it will do that function.
Martha Montgomery